Check the power supply as well as possible fuses or circuit breakers if the air conditioning unit is not working.
Locate the high-pressure limit switch on the compressor access panel and push the switch if the compressor switches off when it should be functioning.
Turn off the air conditioner and clean the fan blades with a clean, soft cloth if the air conditioner is making excessive noise.
Turn off the air conditioner unit if the outdoor temperature is below 60 degrees to prevent frost from forming on the evaporator coils.
Unplug the air conditioner and clean it if the air conditioner is running but is not creating cooler air. If cleaning the unit does not resolve the problem, contact an authorized service technician.